For about a decade many passenger vehicles have come standard with Air Bag Safety systems and in addition to the standard options protecting the driver and front passenger additional safety air bags are available for side impacts and rear passengers.
The first thing that you need to understand is that an Air Bag System is designed to work in unison with your seat belt restraint system so driving without your seat belts is not only illegal in most places it will put your life at risk even if you have the best air bag system.
You can kind of think of it as your cars suspension and shocks. If you simply installed shocks or struts without springs your car would be undriveable and if you rely on your air bags alone your safety system will not work correctly. You may be able to drive your car without springs but it will be about as pretty as getting in an accident and laying on a gurney in transport to the hospital after your head hits the ceiling of your car or a rear impact propels you through the rear window.
So, what are the parts of an Air Bag System?
The Air Bag Module
This unit contains the Air Bag and the inflation device. Because impacts happen so quickly air bags do not rely on Air from a pump to inflate the bag. Instead a small charge expands gas into the bag which is deployed from a quick open cover on your steering wheel, dashboard or other location.
Air Bag System Crash Sensors
The sensors that produce a signal when you are in a crash are located in the front, rear and sides of your vehicle if you have side impact air bags. Some systems will also locate sensors near the ECU to reduce cost. Side impact sensors are often located in a door sill.
Sensors measure the vehicles reduction and change in speed / motion.
Your breaking system can not set off an air bag sensor even under emergency stopping conditions unless there is a fault in the system.
Some cars are also include roll over sensors that tell the ECU computer when the vehicle has rolled over.
The ECU Electronic Control Unit
The ECU reads measurements from the Air Bag Crash Sensors and determines if an air bag should be deployed.
The ECU also runs a diagnostic check on the Air Bag System and will indicate this on your dash board if a problem is found.
Advanced Air Bag ECUs can sense a number of relative factors such as if your seat belts are fastened, seat positions and weights of occupants.
Sensing the weight of an occupant is important for children because some air bags have been found to cause harm to younger riders located in the front seat.
Air Bag System On Off Switch
Some vehicles may allow the deactivation of the passenger side air bag when you are transporting a child in the front seat. Although this might sound evil … as stated above an air bag can sometimes cause more harm when deployed in an area where a child or smaller person is riding.
On / Off switches are available in small trucks and cars when you can not fit a child seat in the back of the passenger compartment easily.
Consumers who wish to have an ON-OFF switch installed “on their own” for either the driver or passenger frontal air bag must apply through NHTSA for permission to have an air bag ON-OFF switch installed.
Pregnant Women
The combination of seat belts and air bags offers the best level of protection to pregnant women, just as it does for other adults. Moreover, pregnant women should follow the same basic air bag safety precautions as other adults.
When buckling up, a pregnant woman should take care to:
- NEVER place the lap belt above or on the belly.
- Adjust the lap belt across the hips/pelvis – below the belly.
- Place the shoulder belt across the chest (between the breasts) and away from the neck.
- Never place the shoulder belt behind the back or under an arm.
Women late in pregnancy may not be able to position their abdomens away from the steering wheel as easily as women in earlier stages. If the vehicle has a tilt steering wheel, pregnant women should make sure the steering wheel is tilted toward the breastbone, not the abdomen or the head.
Final Note
Always wear your seat belt. Advanced frontal air bags are a supplemental restraint system, just like earlier generation air bags, and must be used in combination with a seat belt. All occupants should wear a seat belt or be seated in an appropriate child safety restraint system.
Place children under 13 in the rear seat. Parents and caregivers should always place children under 13 in the rear seat in an appropriate child safety restraint system. The rear seat is the safest place for children.
Read your vehicle owner’s manual. No air bags – even advanced frontal air bags – can be designed to handle every situation. Air bags can still cause serious injury or death to occupants who are not properly restrained and in the proper seating position.
Buying a Used Vehicle
If you are buying a used vehicle with an Air Bag Safety System you should visit the Dealer of that vehicle and obtain proper documentation on its operation.
If in doubt ask them to help you check that the system is functioning correctly and that the absence of a Dashboard indicator light is not simply the light being burnt out but that the system is actually working correctly.
In exchange for you telling the dealer you are an owner of a vehicle that they may at some point in the future service they should be happy to provide a few minutes of their time to provide you all you need to know about your system.